<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>

    <script>

        function a() {
            document.write("3秒跳转")
        }
        function b() {
            document.write("2秒跳转")
        }
        function c() {
            document.write("1秒跳转")
        }
        let i = 3;
        window.setInterval(
            function () {
            if(i == 3){
                a();
                //i--;
                }else if(i==2){
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                //i--;
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                c();
                //i--;
            }else {
                location.href = "https://www.baidu.com";
            }
            i -= 1;
            },10)
    </script>
</head>
<body>

</body>
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